#ifndef _CIRCLE_H_
#define _CIRCLE_H_

#define PI 3.141592

class Circle
{
  public:
    Circle();
    Circle(double);
    double getRadius() const;
    void setRadius(double);
    double getArea() const;
    static int getCircleNumber();
    //static int getCircleNumber() const; // we could only define instant
    //member function as const function, not the static member function as the
    //const function
  private:
    double radius;
    static int numberOfCircle;
};

#endif
